Volcanic rocks

Context

Geological Conservation Review (GCR) sites are selected for,
and grouped according to, GCR blocks, which are site-selection
categories for nationally important Earth science sites.
There are around 100 'blocks' and about 3,000 GCR sites in
Britain. Each 'block' represents a particular geological age
or Earth science theme, such as Marine Permian Stratigraphy,
Jurassic–Cretaceous Reptilia, Caledonian Igneous Rocks and
Quaternary of Scotland.

The volcanic (igneous) geology blocks relate to the formation
of rocks originating from magma (molten rock) according to major
periods of mountain building activity, such as during the
Caledonian mountain-building episode.

Major episodes of volcanic activity form the basis of six
igneous Geological Conservation Review blocks, and these are linked
to mountain-building (e.g. south-west England Igneous), and the
opening of oceans (e.g. Tertiary Igneous).

This list has not been fully standardised at a UK level yet. It is intended to show the principal constituent "feature types" for this reporting category.

Maps - distribution

Distribution of reported interest features.

Map showing the locations of the 10km squares in which at least one condition assessment has been reported. It does not show features that have not yet been assessed.

Maps - SSSI

Current condition of SSSI/ASSI features
Distribution of SSSI/ASSI features showing assessments of favourability (where unfavourable-recovering is counted as unfavourable).

Condition of SSSI/ASSI features, with those currently reported as unfavourable-recovering shown as favourable
The implication of the unfavourable-recovering condition assessments is that at some point in the future these features should become favourable. This map shows the effect of that recovery by counting the favourable and unfavourable-recovering assessments together.

IMPORTANT NOTE: we do not have information on the timescale of the predicted recovery, which may be influenced by many past, natural and human related factors. A sustained sympathetic management regime is more likely to result in favourable condition being attained.

Key: Proportion of assessed features on 10km squares that are favourable:

Condition summary

This lists the 10 different condition assessments and presents a bar chart showing the number of features within the SSSI series. Note that we are unable to estimate the total number of SSSI/ASSI features because we do not have an overall list of notified interest features for these designations.

NB favourable unclassified and unfavourable unclassified have been used in this first six year cycle to get around difficulties in identifying trends in condition as common standards monitoring is implemented. It is expected that these categories will not be used for subsequent assessments of a feature.

Condition assessment - SSSI features

The number and proportion of assessments for SSSI/ASSI interest features falling into each of the condition categories. Note that the �unfavourable� category includes all reports of unfavourable condition except �unfavourable recovering� which is shown as a separate segment.

Adverse activities

The number of interest features where an activity has been reported as being implicated in the "unfavourable" condition of a feature. More than one adverse activity may be reported for each feature.

Management measures

For each "measure" the chart shows the number of interest features where that measure has been taken on a site to improve or maintain the condition of an interest feature. More than one measure may be reported for each feature assessed.

Interpretation

About 70% of the sites with volcanic (igneous) rock features
are accounted for in the report, of which 95% are reported in
favourable condition. This is above the average for
geological features and well above the average for all features
combined. 0.5% of features reported are
unfavourable-recovering.

Most localities for igneous rocks are robust (hard rock) and
less likely to be affected by activities that are damaging to soft
rock or dynamic landscapes. Where they are unfavourable, the
main reason reported is that the geology is obscured, i.e. not
'visible' or 'exposed', probably because of vegetation or scree
cover.